.. code-block:: python

	#!/usr/bin/env python
	import sys
	import pymzml
	from collections import defaultdict as ddict
	
	
	def main(mzml_file):
	    '''
	    Basic example script to demonstrate the usage of pymzML. Requires a mzML
	    file as first argument.
	
	    usage:
	        ./simple_parser_v2.py <path_to_mzml_file>
	
	    Note:
	
	        This script uses the old syntax where the MS level can be queried as a
	        key (Spectrum['ms level']). The current syntax can be found in
	        simple_parser.py
	
	    '''
	    run = pymzml.run.Reader(mzml_file)
	    # print( run[10000].keys() )
	    stats = ddict(int)
	    for n, spec in enumerate( run ):
	        print(
	            'Spectrum {0}, MS level {ms_level}'.format(
	                n,
	                ms_level = spec['ms level']
	            ),
	            end = '\r'
	        )
	        # the old method to obtain peaks from the Spectrum class
	        stats[spec.ID] = len(spec.centroidedPeaks)
	
	    print(
	        'Parsed {0} spectra from file {1}'.format(
	            len(stats.keys()),
	            mzml_file,
	        )
	    )
	    print()
	
	if __name__ == '__main__':
	    if len(sys.argv) < 2:
	        print(main.__doc__)
	        exit()
	    mzml_file = sys.argv[1]
	    main(mzml_file)
